1. Field of the Invention
The present invention relates to a multifunctional apparatus, and more particularly, to a multifunctional apparatus having a reduced number of circuit boards to lower electromagnetic interference (EMI), the circuit boards being connected to one another by connecting units of a short length.
2. Description of the Related Art
A multifunctional apparatus is a single apparatus in which several office automation (OA) devices such as a printer, a scanner, and a facsimile machine are combined. The multifunctional apparatus generally includes a printing unit and a scanning unit. The multifunctional apparatus simultaneously reads document data and prints the data on other papers. The scanning unit is located in an upper portion of the apparatus to be easily opened and closed. Accordingly, in order to supply power and transfer control signals to the scanning unit, a connecting unit is needed to connect a power board, which receives current from an external power source and distributes the current to a circuit board and other devices, and a main board in which a controller to control the circuit board and other devices is mounted.
FIG. 1 is a perspective view schematically illustrating an example of a conventional multifunctional apparatus. FIG. 2 is a perspective view of a layout of a circuit board in the multifunctional apparatus of FIG. 1.
Referring to FIG. 1, a multifunctional apparatus 10 includes a cassette 11 into which paper is loaded and which is attachable to and detachable from a main body, a printing holder 12 into which papers are discharged after printing, a control panel 13 having installed therein control buttons to control the multifunctional apparatus 10, a scanning unit cover 14 which is installed to rotate and move up and down from the main body, a paper supplier 15, onto which documents to be scanned are placed, and a scanning holder 16 into which the scanned papers are discharged after scanning.
If the scanning unit cover 14 moves upwards, a scanning plane (not shown) covered by the scanning unit cover 14 is exposed. A scanning module (not shown), capable of sliding and projecting lights to scan the papers, is installed below in a lower surface of the scanning plane.
Referring to FIG. 2, a power board 21 which receives current from an external power source and distributes the current to other circuit boards and devices, and a main board 22, in which a controller to control other circuit boards and devices is installed, are disposed parallel to a lower surface 34 of the multifunctional apparatus 10.
A scanning unit board 24, which supplies current to a scanning unit (not shown) and which reduces signals to control the scanning unit, is installed on an upper surface 32 of the multifunctional apparatus 10. In addition, a connecting board 23 to connect the main board 22 and the scanning unit board 24 is disposed on a surface 33 of the multifunctional apparatus 10.
The power board 21, the main board 22, the connecting board 23, and the scanning unit board 24 are connected to each other. That is, the power board 21 and the main board 22 are connected by a first connecting unit 25, the main board 22 and the connecting board 23 are connected by a second connecting unit 26, and the connecting board 23 and the scanning unit board 24 are connected by a third connecting unit 27.
As shown in FIG. 2, the second connecting unit 26 and the third connecting unit 27 are perpendicular to each other. The connecting board 23 may be regarded as a connecting unit to connect the second connecting unit 26 and the third connecting unit 27 which connect the main board 22 and the scanning unit board 24.
In this case, a connecting distance between the main board 22 and the scanning unit board 24 is long, and thus, it is effective that some functions of the main board 22, related to the scanning unit board 24, be transferred to an extra board which is placed near the scanning unit board 24. Therefore, the connecting board 23 is additionally formed and a length of the second and third connecting units 26 and 27 becomes long.
As such, the quality of signals through the connecting units 26 and 27 is lowered and the electromagnetic interference (EMI) therebetween becomes worse. Given that an antenna operates most efficiently when the length of the antenna is equal to one fourth of a wavelength, the second connecting unit 26, the third connecting unit 27, and the connecting board 23 act as a good antenna at a frequency below 300 MHz, and electromagnetic energy radiates via the connecting units 26, 27 to circuit boards inside the apparatus, thereby affecting the printing, scanning, or faxing operations.